What lipoprotein is responsible for transporting cholesterol back to the liver form periphery?

The lipoprotein responsible for transporting cholesterol back to the liver from the periphery is high-density lipoprotein (HDL), also known as "good cholesterol." HDL plays a crucial role in the reverse cholesterol transport process, which helps remove excess cholesterol from the arteries and transport it back to the liver for elimination. Here's how HDL functions in this process:

1. Cholesterol Efflux: HDL particles circulate throughout the body and acquire cholesterol from peripheral tissues and cells. This process is facilitated by specific proteins on the HDL surface, such as apolipoprotein A-I (ApoA-I), which promotes the efflux of cholesterol from cells.

2. Cholesterol Esterification: Once HDL acquires cholesterol, it undergoes esterification, where the free cholesterol is converted into cholesterol esters by an enzyme called lecithin-cholesterol acyltransferase (LCAT). Cholesterol esters are less soluble and more stable, making them suitable for transport within the bloodstream.

3. Reverse Cholesterol Transport: HDL, enriched with cholesterol esters, transports the cholesterol back to the liver through a process called reverse cholesterol transport. During this process, HDL interacts with various receptors and proteins in the liver, including the scavenger receptor class B type I (SR-BI).

4. Cholesterol Uptake by the Liver: The interaction between HDL and SR-BI facilitates the selective uptake of cholesterol esters into the liver cells. Once inside the liver, the cholesterol can be further metabolized or excreted as bile salts.

By promoting the reverse cholesterol transport and removing excess cholesterol from the arteries, HDL helps prevent the buildup of plaque and reduces the risk of developing cardiovascular diseases such as atherosclerosis, heart attacks, and strokes. Maintaining healthy HDL levels is essential for overall heart health.